The P-39 was an unusual design when it appeared in 1937. Among its many unorthodox design features are the mounting of the engine behind the pilot, the use of automobile type doors on the sides of the cockpit, and tricycle landing gear. Although performance was good at low altitudes, it was poor higher up but a large nose-mounted cannon made it effective for ground attack. Pima's example is in the marks of 110th TRS, New Guinea, 1944